Tunnel kiln



' pr 15 1924 HAQE H. M. ROBERTSON r l TUNNEL KILN y Original Filed July 24. 1920 s Patented Apr. l5, i924.

narran erratas atacan entier oer-arc.

HARRY IMI. ROBERTSON, OF ROCKVLLE, MARYLAND, -ASSIGNOR TO AMERICAN DRESS- i LER TUNNEL KILNS, INC., OF NEW YORK, N. Y., A CORPORATION F NEW YORK. i

TUNNEL man.

Application led July 24,1920, Serial N. 398,603. yRenewed lSeptember 12, 1923.

To all whom t may con-cern.:

Be it` known that I, HARRY M. ROBERTSON, citizen of the United4 States, and resident of Rockville, in the county of Montgomery and State of Maryland, have invented certain new and useful Improvements in Tunnel Kilns, of which the following is a specilication.

The objectof my present invention is to provide a simple and effective combination with a continuous tunnel kiln', of an external recuperator to utilize the hot products of combustion 'withdrawn from;r the kiln, in preheating air employed to supl port combustion in the kiln.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forminga part of this specification.

For a better understanding of the invention,

however, reference should be had to the accompanying drawings and descriptive matter in which lf have 'illustrated and described a preferred embodiment ofthe invention.

Of the drawings;

Fig. l ,is a diagrammatic plan view of a portion yof a continuous tunnel vkiln embodying my invention; i

line 2-2 of Fig. l; g.

Fig. 3 is a section onthe line 3-3 of Fig. 2

gig. 4 is a plan view of the. recuperator;

an Y

Fig. 5 is a partial transverse section taken on the line 5-5 of Fig. 1.

ln the drawings I have illustrated the use of my invention in connection with a continuous tunnel kiln A, having combustion chambers B located therein at opposite sides of the pathway through the kiln for' the goods to be heated. The chambers B are formed with channel.J b in their wallswhereby a directed convection current circulation of the kiln atmosphere is maintained as set forth in the patent to Conrad Dressler No. 1,170,428.

As-shown the outlet ends ot the combuse@ from the entrance end of the kiln. Fuel gas Fig. 2 is an elevation in section-on the,

tion cham-,bers B extend to the entrance or oil is supplied, to each burner inlet from fuel supply mainsD, and air for the combustion of the fuel is supplied to each burner inlet through a corresponding branch pipe F2 from 4an air main E.A As shown there are two air mains E located above the roof of the kiln chamber and. extending Alongitudinally of the latter one adjacent lower end through a manifold to the crossf over main E. At their upper ends the ipes F2 are connected through a manifold to the delivery pipe G from one or 'more blowers Gr, two being shown, for forcing atmospheric air through the pipes F 2 and thence through the mains E and E and the branch pipes E2 to the burner inlets C.

The products of combustion pass out of the combustion chambers B through outlet assages B into a duct B2 which opens to t e recuperator chamber f at the lower end of the latter. To the upper end of the recuperator chamber f is connected a waste gas outlet pipe H which-runs to a suitable draft creating device. As shown the draft creating means comprises an ex-` haust fan I with its outlet connected to a stack J.

pended from the rods A7 connecting theupper ends of the usual buckstays A6 supporting the outer brick walls or the kiln.

VViththis arrangement` of the supporting mains E, the relative contraction and eX- pansionof the mains and the masonry work of the kiln may occur without creating trouble while a convenient disposition ot the mains'is obtained and they are effectively insulated against heat losses with.

\ 'practically no additional expense for such insulation. The general arrangement of the recuperatoi and the kiln is one which' lends to economy .in ground space occupied and in construction cost, as Well as to au eiicient heat recovery. It will be apparent that in operation the recuperator acts on the :counteriow Iprinciple, and that the flow resistance to t e passage of the hot products through the recuperator is relatively small,

thus making it easy to maintain the proper f fdraft suction at the outlets of the com- -bulstion chambers. Theinvention is especially adapted for use in connection with-a 1 ytunnel kiln of the type shown in which,

as in annealing casting iron, it is desirable in.,v order to'shorten the length of the kiln,

or for other reasons to have the entrance end of the kiln quite hot, so that the products of' combustion are Withdrawn from the kiln at va relatively high temperature. `Vlhile in accordance with the provisions of the lstatutes I have illustrated and described the preferredembodiment of my in- --vention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed herein Without departing from the spirit of my invention and that certain fear tures of my invention may sometimes be used k'to advantage Without a corresponding use of other features.

Having new I claim as new and' desire to secure' byLetters Patent, is: f 1. The combination with av continuous `tunnel kiln having an outlet for products described my invention, whatl tending longitudinally of said kiln and located above the latter. 2. The combination with a continuous tunnel kiln comprising a kiln chamber with amasonry wall and a heat insulating cover for the latter and having an outlet for products of combustion adjacent its entrance end and burner inlets at the sides of the kiln at points remote from the entrance end thereof, of a recuperator connected to said outlet and al conduit system for conveying air preheated in said recuperator to said burner inlets comprising a portion extending longitudinally of said kiln and embedded in said insulation cover.

3. The combination in a continuous tunnel kiln comprising an elongated kiln chamber formed with masonry walls and having burner inlets and a metallic reinforcingstructure therefor comprising buckstays at the sides of the kiln andi-tie rods connecting buckstays at opposite sides of the kiln, of an air supply conduit system` including a portion extending longitudinally of the kiln and supported by said structure and 'comprising-outlet connections opening to said burner inlets. A A

4. The combination in a continuous tunnel kiln comprising an elongated kiln chamber formed with masonry Walls and havin burner inlets and an insulating cover, an a metallic reinforcing structure for said walls comprising `buckstays at the sides of the kiln and tie rods connecting buckstays at opposite sides of the kiln, of an air supply conduit system including a portion eX- tending longitudinally of the kiln and embedded in said insulation and comprisinor I outlet connections to said burner inlets, an

`adjustable hangers by which said conduit portion is suspended from said tie rods.,

Signed at New Castle` in the county of Lawrence and Stateof Pennsylvania, this 15th day of July, A. D. 1920.

v H. M. ROBERTSON. 

